Metallization of fabrics

ABSTRACT

A METHOD OF PRODUCING A METALLIZED FABRIC BY A TRANSFER PROCESS AND SUCH METALLIZED FABIC SO PRODUCED WHEREIN A TRANSFER SUPPORT IS FIRST COATED WITH A SUBSTANTIALLY NON-ADHERENT VARNISH, A METTALLIC LAYER IS APPLIED OVER SAID VARNISH, AND A COATING OF A THERMOPLASTIC ADHESIVE IS APPLIED OVER PRESELECTED AREAS OVER SAID METALLIC LAYER. AFTER DRYING, THE ADHESIVE COATED METALLIC LAYER IS APPLIED TO THE SURFACE OF THE FABRIC WITH SUFFICIENT HEAT AND PRESSURE SO AS TO BOND THE METALLIC LAYER TO THE FABRIC WITHOUT SUBSTANTIALLY IMPREGNATING THE FABRIC WITH THE THERMOPLASTIC ADHESIVE. THE FINISHED METALLIZED FABRIC IS PRODUCED BY STRIPPING AWAY THE TRANSFER SUPPORT.

United States Patent 3,589,962 METALLIZATION 0F FABRICS Georges A. Boujour, Lyon-Bron, France, assignor to La Cellophane, Societe Anonyme, Paris, France No Drawing. Filed July 1, 1968, Ser. No. 741,294 Claims priority, application France, Aug. 8, 1967, 117,167 Int. Cl. 1344c 1/14 US. Cl. 156233 7 Claims ABSTRACT OF THE DISCLOSURE A method of producing a metallized fabric by a transfer process and such metallized fabric so produced wherein a transfer support is first coated with a substantially non-adherent varnish, a metallic layer is applied over said varnish, and a coating of a thermoplastic adhesive is applied over preselected areas over said metallic layer. After drying, the adhesive coated metallic layer is applied to the surface of the fabric with sufficient heat and pressure so as to bond the metallic layer to the fabric without substantially impregnating the fabric with the thermoplastic adhesive. The finished metallized fabric is produced by stripping away the transfer support.

The present invention is directed to a process of producing a metallized fabric and such metallized fabric so produced; more particularly, the present invention is directed to such a process for producing a metallized fabric wherein the metal coating is transferred to the fabric by way of a transfer support.

Previous processes have been known for producing metallized fabrics wherein the metallic layer or coating is deposited on an intermediate or transfer support and transferred from such support to the fabric to be coated by use of an adhesive layer. Such processes, however, have not been free from certain inherent disadvantages and deficiencies.

In order that the very bright effect which is desired to be imparted to the fabric by the metallization may be preserved, such prior art processes assume that the adhesive layer deposited on the fabric has a very smooth surface. Such requirement, however, tends to account for the partial obliteration of the pores of the metallized fabric. Thus, using such prior art processes, it is necessary to deposit a relatively heavy adhesive layer, which penetrates deep into the fabric, thereby destroying its pliability and modifying its handle. Consequently, such processes are unsuitable for metallizing porous and pliable fabrics, such as jersey fabrics, which are in great demand for use in the fashion industry.

In accordance with the persent invention, however, such deficiencies and disadvantages of prior art processes are eliminated by enabling the finest fabrics to be metallized Without causing any loss in their natural pliability and handle. Thus, the process of the present invention permits such fabrics to be metallized not only uniformly over their entire surface without the inherent disadvantages of prior art processes, but, in addition, the process of the present invention also allows for the selective metallizing of the fabrics, thereby providing the production of any design previously estabilshed. In addition, the process of the present invention has as a distinct advantage the deposition of a varnish at the same time as the deposition of the metal layer, such varnish protecting the fabric after transfer.

Accordingly, it is a principal object of the present invention to provide a process for producing metallized fabrics and such metallized fabrics so produced which process eliminates the inherent deficiencies and disadvantages of prior art processes.

Patented June 29, 1971 A further object of the present invention comprises a process for producing metallized fabrics wherein a transfer support is utilized, an adhesive coated metallic layer being transferred from such support to the fabric to be metallized, the support being previously coated with a varnish layer.

A still further object of the present invention comprises a method of producing a metallized fabric wherein any and all fabrics can be metallized without loss of their natural pliability and handle by the application of a metal layer uniformly and selectively over the surface of the fabric, the adhesive adhering such metal to the fabric not substantially impregnating the fabric to be metallized.

Still further objects and advantages of the process and product of the present invention will become more apparent from the following more detailed description thereof.

. The process of the present invention eliminates the inherent deficiencies and disadvantages of conventional prior art processes by allowing the uniform distribution of a metallic layer or coating on a fabric without impairing the natural pliability and handle of the fabric that is metallized by depositing a layer of non-adherent varnish on a smooth, flexible sheet of a temporary or transfer support with subsequent deposition of the metal layer and coating of such layer with a thermoplastic adhesive over preselected areas thereof. After drying of the adhesive, the adhesive coated metallic layer is applied to the surface of the fabric with sufficient heat and pressure to reactivate the adhesive properties of the thermoplastic composition. Upon stripping off of the temporary support, a metal layer or coating adhered to the fabric is produced.

As used throughout the instant specification and claims, the term fabric is meant to embrace not only conventional woven fabrics, but also tricot fabrics, unwoven fabrics, felts, and in general all materials which are related to a textile article. In this respect, the process of the present invention is such that by allowing the metallization of such textile fabrics without any tendency to cause such fabrics to lose their natural pliability and handle, the process of the present invention is applicable to all and any such fabrics. In this respect, wherein conventional processes could not be applied to porous and pliable fabrics because of the destruction of the pliability and modification of the handle of such fabrics, the process of the present invention does not possess such inherent deficiencies and disadvantages. Accordingly, there are no restrictions whatsoever with respect to the fabric base which can be metallized in accordance with the present invention.

The transfer or temporary support employed in accordance with the process of the present invention can comprise a conventional plastic film having a smooth surface, and the mechanical resistance and temperature stability sufiicient to allow it to be metallized in vacuo and withstand the hot transfer operation. Thus, for example, such films can comprise regenerated cellulose, cellulose derivatives, e.g. cellulose acetate or cellulose butyrate, synthetic plastic materials, e.g. polyvinyl chloride, polyamides, polyvinylidene chloride, polyvinyl acetate, polyvinylpyrrolidone, polyetherand polyester-based polyurethanes, and even synthetic and natural rubbers or papers impregnated with plastic materials. Preferred materials employed in accordance with the present invention as a temporary or transfer support include polyester films, e.g. films of polyethylene terephthalate, which films have particularly suitable dimensional stability, mechanical characteristics and strength.

In accordance with the present invention, it is advantageous to employ a thin flexible film having a smooth surface. In this respect, the smoothness of the surface of the temporary or transfer support will dictate the smoothness of the metallized layer applied to the fabric. Accordingly, it is quite obvious that such temporary or transfer support should be as smooth as possible. In addition, to facilitate stripping of a temporary or transfer support after application of the metallized coating through the application of heat and pressure, it is advantageous that such temporary or transfer support be very thin and flexible. Accordingly, films of approximately 25 to 50 microns in thickness are preferred for purposes of the present invention.

In accordance with the process of the present invention, any substantially non-adherent varnish compatible with the transfer support can be utilized. The substantially non-adherent characteristics of such varnish are those which facilitate stripping away of the transfer support while leaving the layer of varnish on the metallized fabric so as to protect the same from damage by water or certain solvents and stains, etc. In this respect, it is preferable to select a varnish capable of providing after transfer to the fabric a surface protection to the metallic coating or layer to protect the same from damage by water or certain solvents and to permit stains to be easily removed. By providing a varnish which does not substantially adhere to the transfer support, a metallized fabric is obtained which, because of the adherence of the varnish to the metallic layer, confers a maximum of brilliance to such layer. For purposes of the present invention, the varnish layer is generally applied in a thickness in the order of about two microns to five microns, such thickness having the advantage of not in any way altering the pliability of the fabric.

For purposes of the present invention, any conventional varnish material can be utilized. Thus, for example, such a varnish conventionally employed can comprise a suitable varnish having a crosslinkable acrylic base, e.g. a base of acrylic acid, methacrylic acid or esters thereof, a nitro cellulose base, a polymerized vinyl chloride base, a polymerized vinylidene chloride base, and mixtures and copolymers of the same. For purposes of the present invention, however, those varnishes comprising a crosslinkable acrylic base are preferred. Such varnishes are generally dissolved in an organic solvent, e.g. a conventional ketonic solvent such as methyl ethyl ketone, methyl isobutyl ketone, etc., to which a plasticizing additive, e.g. ethyl acetate, has been added.

Of course, all of the above exemplified varnish bases that can be employed in accordance with the present invention are only exemplary of the various and sundry conventional varnishes which can be employed in accordance with the process of metallizing fabrics such as set forth in accordance with the present invention. Again, the only necessary characteristic of such varnish is that such varnish be substantially non-adherent to the temporary or transfer support to which it is applied.

In addition to the employment of a clear varnish such as those set forth above, it is also within the province of the present invention to employ a colored varnish by incorporating various pigments, for example, gilding, in such varnish so as to give the final product any desired appearance.

The metallization of the varnished base of the temporary or transfer support is accomplished by any conventional manner. Thus, for example, such metallization can be generally accomplished under vacuum by sputtering the metallic film on the varnished surface of the plastic support by any known technique of metallizing films of plastic materials. Such conventional techniques of metallizing plastic films are well known in the art and are incorporated herein by reference. It is pointed out in this respect that the present invention is not predicated upon a particular manner of producing the metallic layer or coating, but is predicated upon the elimination of disadvantages and deficiencies of the prior art by providing a certain sequence of process steps in the preparation of the metallized fabric.

Any and all metals which lend themselves to such conventional metallization processes can be employed in accordance with the present invention. Thus, for example, suitable metals include aluminum, tin, zinc, chromium, etc. However, of all these metals, aluminum is especially preferred in accordance with the present invention, the deposition of aluminum allowing for the production of a light weight metallized fabric of exceptional brilliance.

Again, in order to retain the pliability of the fabric metallized in accordance with the present invention, it is desirable to deposit a metal layer which is as thin as possible. Therefore, it is preferable in accordance with the present invention to apply a metal layer of from about 0.05 micron to 0.1 micron in thickness. Of course, where desired for particular purposes, slightly lesser or greater thicknesses of the metallic layer can be employed. This, of course, is only a matter of taste dictated by the esthetic qualities and end use to which the fabric is employed.

After application of the metal layer to the varnished face or surface of the transfer support in accordance with the present invention an adhesive layer is then deposited over preselected areas of the metal coated surface, such adhesive layer being applied so as to unite the metallic coating covered by the protective varnish with the fabric to be metallized. Generally, the adhesive layer is applied over the whole of the metallic coating; however, where it is desired to produce certain designs or other ornamental effects on the metallized fabric it is possible to apply the adhesive only over preselected areas not comprising the whole of the metallized support so as to produce a final metallized fabric of a particular de sign by application of only that portion of the metal coating to which the adhesive has been applied.

In accordance with the present invention any conventional thermoplastic adhesive normally used for the coating of fabrics may be utilized, such adhesives having the requisite qualities of pliability and adhesion when activated by the use of heat and pressure. Thus, for example, suitable adhesives are those based upon acrylic or vinyl monomers or copolymers of such compounds. Exemplary adhesives therefore include homopolymers and copolymers of acrylic acid, methacrylic acid and lower 'alkyl esters thereof, e.g. methyl acrylate, ethyl acrylate, isopropyl acrylate, methyl methacrylate, ethyl methacrylate, isopropyl methacrylate, vinyl acetate, vinyl chloride, vinylidene chloride, vinyl alcohol, vinylpyrrolidone, etc. In general, however, any elastomeric adhesive having the requisite adhesion when activated by the use of heat and pressure can be employed in accordance with the present invention. The above exemplified adhesives are therefore only illustrious of those adhesives conventionally employed in the coating of fabrics, the present invention not being predicated upon the use of any particular adhesive material. In general, the adhesives employed in accordance with the present invention are applied to the metallized surface of a temporary or transfer support as an aqueous emulsion since such aqueous emulsions are generally preferable as such emulsion do not in any way tend to attack the varnish on the opposite face of the thin metallic film. The adhesives should have a neutral or substantially neutral pH so as to not present any possible problem of attack of the thin metal film. Therefore, if an acidic adhesive is employed, such adhesive should be first neutralized by the use of ammonia or other neutralizing agent; and if an alkaline adhesive is employed, such adhesive can be first neutralized by the use of acidic acid or similar acidic neutralizing agent.

The adhesives may also have customary inert fillers added thereto, such as zinc oxide or titanium dioxide, such fillers or pigments having the effect, for example, of reducing the stickiness of increasing the opacity to light of the deposited adhesive. This, therefore, results in improving the brilliance of the metal. The nature and the quantity of these fillers also depends somewhat on the nature of the fabric. On a fairly loose fabric, such as a jersey fabric, it is appropriate to use more filler, for example,

than used on a very tightly woven and slippery material such as a nylon fabric.

It is important that the adhesive finish should form a layer which is as thin as possible, so that it remains on the surface of the fabric without passing through it; in this way, the layer remains perfectly smooth at the moment of transfer and, since it reproduces the surface of the transfer support, it does not alter the brilliance of the metallic coating, which is as perfect as that which is obtained by the metallization of the film.

The reverse side of the fabric is not modified in accordance with the present invention, and this is an important advantage for the production of unlined garments. In addition, the very small thickness of the adhesive layer only alters very slightly the permeability of the fabric. Finally, since the thin adhesive film' does not substantially penetrate into the fabric, its handle and its pliability are unmodified. As a result, the process according to the present invention, contrary to the known techniques, is applicable to extremely porous and pliable fabrics, such as jersey fabric.

The adhesive applied to the metallized, varnished surface of the transfer or temporary support can be deposited in any conventional manner, e.g. by brushing, dipping, spraying, etc. As set forth previously, the adhesive coating should be applied in a manner such that the smallest possible quantity, preferably less than 50 grams per square meter and, more preferably, between and 30 grams per square meter is applied. The adhesive coating may then be dried, for example, in hot air or with infrared rays or any other suitable conventional drying means.

At this point in the process of the present invention the support bearing the successive layers of varnish, metal and dried adhesive is ready for application to the fabric by heat and pressure so as to produce the desired metallized fabric. The support bearing the three successive layers may not be used immediately and, Where desired, may be reeled up and kept for later application to the fabric. This is an advantage associated with the use of the dried thermoplastic adhesive, since until the application of subsequent heat and pressure the adhesive-coated surface remains inert and substantially non-tacky and thus can be kept for substantial periods of time before application.

The transfer process employed in accordance with the present invention may be conveniently effected in a calender machine heated to a temperature in the order of 90 to 100 C. depending on the nature of the fabric and, of course, the nature of the thermoplastic adhesive utilized. In this respect, the conditions employed in the transfer process need only be those which can effectively activate the thermoplastic adhesive While not in any way effecting the fabric to which the metallized coating is applied.

After the application of the adhesive by such transfer process, the assembly comprising the temporary or transfer support and the metallized fabric may then pass through a cooling means, e.g. over a cooling cylinder, after which the fabric coated with the adhesive, metal film and varnish can be separated from the temporary or transfer support by stripping away such support, the support and metallized fabric being reeled separately. Generally, it is possible for the temporary or transfer support, especially if it is prepared from a polyester film, to be recovered for reuse.

As stated previously, instead of covering the entire metallized surface with an adhesive applied uniformly thereover, it is possible in accordance with one embodiment of the present invention to apply the adhesive locally in preselected areas so as to form a decorative pattern. This result can be obtained by any known process, for example, by using a flexographic technique. In this way, the transfer of the metallic film will only occur at those areas where the adhesive has been deposited on the fabric, thus producing the chosen design or pattern.

As can be seen from the above, the process of the present invention comprises a novel combination of steps to provide a metallized fabric by a transfer process comprising (1) coating a temporary or transfer support with a substantially non-adherent varnish; (2) applying a metallic layer over said varnish-coated transfer support; ,(3) coating said metallic layer over the entire surface or preselected areas less than the entire surface with a thermoplastic adhesive; (4) drying said adhesive; (5) applying the adhesive-coated metallic layer to the surface of the fabric to be metallized with the application of sufiicient heat and pressure so as to bond the metallic layer to the fabric without substantially impregnating the fabric with the thermoplastic adhesive; and (6) stripping away the transfer or temporary support to provide the desired metallized fabric.

Thus, in accordance with the above process, it has been found possible to produce a metallized fabric having a brilliant esthetic appearance without in any way adversely affecting the inherent pliability and handle of the fabric material. In this respect, the process of the present invention and the product of the present invention, i.e. the metallized fabric produced by the process outlined above is unexpectedly superior to conventional prior art processes and products.

The present invention will now be illustrated by reference to the following specific examples. It is to be understood that such examples are presented for purposes of illustration only, and the present invention is in no way to be deemed as limited thereto.

EXAMPLE I Using a coating machine provided with a heliographic cylinder, a polyethylene terephthalate film 25 microns thick had deposited thereon a 2 microns thick varnish layer, consisting of commercially available acrylic resins marketed by Organo Systhese, comprising 25 parts of Ucexol S and 75 parts of Ucexol SA, in solution in a solvent formed by parts of methyl ethyl ketone and 20 parts of ethyl acetate.

The film thus coated was then metallized under vacuum With aluminum on the varnished face.

Using a machine which successively carried out the coating and the calendering, the metallized face of the film had deposited thereon, at the rate of 30 grams/square metre of dry materials, an aqueous layer of acrylovinyl emulsion consisting of Cinacryl 4312 marketed by Reichold Bekacite, to which are added 5% of titanium dioxide, the pH of the adhesive emulsion having been brought to 7 by means of ammonia.

This adhesive layer was dried with infra-red rays in a conventional drying tunnel, and then the assembly was directly calendered in a calender heated to 100 C. onto a cellulose acetate jersey fabric.

After passing over a cooling cylinder at ambient temperature, the polyethylene terephthalate film was separated from the varnish and Wound separately. The fabric coated with a metallic film of high brilliance was found to have retained all its pliability.

EXAMPLE II Example I was repeated using a fabric made of nylon instead of cellulose acetate and laminating in a calender at C. A similar result was obtained.

EXAMPLE III Example I was repeated using as the adhesive an elastomer EC 826 supplied by Minnesota Mining and Manufacturing Corp, in solution of 20% ethyl acetate. When this layer had dried, it was not self-adhesive.

Instead of being calendered directly, this material was then pre-cut in accordance with decorative designs and laminated onto a nylon cloth in a press, the plates of which were heated to 130 C. In this way, decorative metallized elements were obtained which were associated as desired on making-up with non-metallized elements.

EXAMPLE IV Example I is again repeated except that the fabric metallized in accordance with the present invention comprises wool. Substantially equivalent results are obtained.

EXAMPLE V Example II was repeated except that the varnish utilized comprised the following composition: copolymer of vinyl chloride and vinyl acetate in a proportion of 87% chloride for 13% acetate-100 grams, parafiin 3 grams in solution in 600 grams of methyl ethyl ketone.

Again, substantially equivalent results are obtained.

EXAMPLE VlI Example I was again repeated utilizing a varnish comprising a conventional nitrocellulose base dissolved in ethyl acetate in a proportion of 100 grams of solid nitrocellulose base in 400 grams of solvent. Again, as in Example I, a metallic film of high brilliance was produced, the fabric retaining all of its pliability.

EXAMPLE VII When Example I is again repeated except that the metallized layer comprises chromium instead of aluminum, a substantially equivalent product having a brilliant chromium surface is produced. Again, by employment of the process of the present invention, the fabric to which the chromium coating is applied does not lose its inherent pliability or handle.

While the present invention has been described primarily with respect to the foregoing specific examples, it is to be understood that the present invention is in no way to be deemed as limited thereto but must be construed as broadly as all or any equivalents thereof.

It is claimed:

1. A method of producing a metallized fabric by a transfer process which comprises:

(1) coating a transfer support with a varnish which is substantially non-adherent to said transfer support but adherent to a subsequently applied metallic layer;

(2) applying said metallic layer over said varnish;

(3) coating said metallic layer over preselected areas with a thermoplastic adhesive;

(4) drying said adhesives;

(5) applying the adhesive coated metallic layer to the surface of a fabric with sufficient heat and pressure so as to bond said metallic layer to said fabric without sufficiently impregnating said fabric with said thermoplastic adhesive; and

(6) stripping away said transfer support to provide the desired metallized fabric.

2. The method of claim 1 wherein said adhesive is coated over the entire metallized surface of the transfer support.

3. The method of claim 1 wherein said adhesive is applied over a portion of the metallized surface of the transfer support so as to form a design on said fabric.

4. The method of claim 1 wherein said metallic layer comprises aluminum.

5. The method of claim 1 wherein said varnish is applied at a thickness of about 25 microns; said metallic layer is applied at a thickness of about 0.050.1 micron; and said thermoplastic adhesive is coated at a rate of less than grams/sq. meter.

6. The method of claim 1 wherein said thermoplastic adhesive is coated at a rate of about 10-30 gram/sq. meter.

7. The method of claim 6 wherein said metallic layer comprises aluminum.

References Cited UNITED STATES PATENTS 2,702,580 2/1955 Bateman l56332X 2,703,772 3/1955 Keithly 156--23'9X FOREIGN PATENTS 166,093 5/1952 Australia 156233 786,098 11/1957 Great Britain 156233 LELAND A. SEBASTIAN, Primary Examiner U.S. C1. X.R. 

